The identification of fat density by unenhanced CT within an adrenal mass is highly suggestive of myelolipoma. Adrenal collision tumors which involve a myelolipoma are uncommon, though the involvement of adenomas and pheochromocytomas has been reported. We describe a case in which an adrenal collision tumor consisting of an adrenocortical carcinoma and myelolipoma, presented as a large fat-containing adrenal soft tissue mass.